Capsular membrane treatments to increase accommodative amplitude

ABSTRACT

Methods and apparatus treat the lens capsule so as to increase accommodation of the eye. The treatment of the lens capsule may comprise treating a portion of the lens capsule so as to stiffen the treated portion and improve accommodation of the eye. The intermediate portion of the lens capsule may located between an optically used central portion of the lens capsule and a peripheral portion of the lens capsule connected to zonules of the eye. The stiffened intermediate portion of the lens capsule can improve coupling of the peripheral portion of the lens capsule to the central portion of the lens capsule, such that an amount of accommodation of the optically used central portion of the lens is increased. As the force of the lens capsule to a lens disposed within the lens capsule is increased, the lens may comprise the natural lens of the eye or an artificial lens such as an accommodative IOL. The treatment of the eye to stiffen the intermediate portion may comprise application of one or more of an energy or a substance to the intermediate portion.

This application is a continuation-in-part of and claims priority toU.S. application Ser. No. 12/507,780, filed on Sep. 30, 2009, which ishereby incorporated by reference in its entirety for all purposes as iffully set forth herein.

BACKGROUND OF THE INVENTION

The present invention relates to accommodation of the eye and treatmentof presbyopia.

The eye has a cornea and a lens. The cornea and lens focus light on aretina such that the person can perceive the image with the retinalocated on the back of the eye. When the image on the retina is focused,the image appears sharp to the patient. However, when the image is outof focus, the image appears blurred. An eyeglass prescription to correctfar vision of the eye can be referred to clinically as a refraction ofthe eye, and the measured refraction of the eye can include a sphere, acylinder and an axis of the cylinder. Corrective lenses can beprescribed based on the refraction of the eye such that optical errorsof the eye such as nearsightedness, also referred to as myopia, andfarsightedness, also referred to as hyperopia, can be corrected.Nearsightedness corresponds to an eye having too much optical power suchthat objects near the eye appear in focus and distant objects appearblurred. With a nearsighted eye, lenses having negative optical powercan be used to correct the refractive error of the eye. Farsightednesscan refer to an eye not having enough optical power such that positivelenses placed in front of the farsighted eye can correct near vision.

In the normal healthy eye, the lens of the eye can accommodate to bothnear and far distances of the object viewed such that the image of theobject is focused on the retina and remains sharp to the patient. Forfar vision, the ciliary muscles of the eye can relax and adjust the lensto focus on a far object that may be several meters away. For nearvision, the ciliary muscles of the eye can constrict and adjust the lensto focus on a near object. The near object can be located at a distancesuitable for reading, for example. The eye can accommodate with movementof the lens to focus on objects at intermediate distances.

With age the accommodation of the eye can decrease such that a personwith good distance vision may benefit from lenses to see near objectsclearly. The decrease of accommodation of the eye corresponding topresbyopia may be related to a stiffer crystalline lens that decreasesthe accommodative amplitude of the lens of the eye in at least someinstances. People who are near sighted and wear glasses for distancevision may find glasses that correct sight for far vision do not providenear vision correction in at least some instance. This loss ofaccommodation of the eye can be referred to as presbyopia.

Although many forms of optical correction and devices have been proposedto treat presbyopia, at least some of these approaches have one or moredeficiencies such that the prior correction of presbyopia may be lessthan ideal in at least some instances. Although reading glasses can beeffective when worn, in at least some instances a person may not haveglasses and need near vision. Also, switching from near vision to farvision with reading glasses can be less than ideal in at least someinstances. Although bifocals are available, such corrective lenses mayprovide less than ideal results in at least some instances such as whena person engages in water sport or sweats such that the correction ofthe lenses can be at least partially distorted.

Although it has been proposed to reduce the stiffness of the naturalcrystalline lens through laser treatment allowing for improvement in theability of the crystalline lens to change power, in at least someinstances it is possible to create a premature cataract. Also,treatments of the lens can potentially result in changes in refractionthat may require the patient to wear glasses in at least some instances.Further, at least some tissue treatments can be unstable in at leastsome instances such that the treatment results in no more than atemporary change to the eye in at least some instances. For example,electrocautery of the lens capsule may result in decreased thickness ofthe lens capsule that may contribute to cataract formation and may berelated to unstable refraction of the eye in at least some instances.

Patients who receive intraocular lenses (hereinafter “IOLs”) may have noeffective accommodation, and may be considered presbyopic in at leastsome instances. For example, although IOL surgery to replace a cataractof the natural lens of the eye can be effective in restoring vision ofthe patient, such patients cannot accommodate effectively in at leastsome instances.

Although multifocal lenses have been proposed, such lenses can result inundesirable visual phenomenon (hereinafter “dysphotopsia”) in at leastsome instances. Although multifocal lens may provide a first opticalcorrection for near vision and a second optical power for distancevision, the light rays having the second optical power for near visionmay provide visual phenomenon such as halos for a distant object, forexample when the patient views a distant object.

One promising approach to treat patients who have received IOLs forcataract surgery has been to introduce an accommodating IOL. However,such IOLs have resulted in less accommodation than would be ideal andcan be more difficult to implant in at least some instances. Also,recovery time of accommodating IOLs may be longer than anon-accommodating IOL, in at least some instances. Also, theaccommodative abilities may not be restored as would be ideal in atleast some instances. Though vision may be improved, the degree ofimprovement can vary among patients and may be less predictable thanwould be ideal in at least some instances.

In light of the above, it would be desirable to provide improved methodsand apparatus for treating vision that overcome one or more of the abovementioned limitations of the prior approaches. Ideally such methods andapparatus would restore accommodation to provide near and far visioncorrection with reduced side effects.

SUMMARY OF THE INVENTION

Embodiments of the present invention provide treatment of the lenscapsule so as to increase accommodation of the eye. The treatment of thelens capsule may comprise treating an intermediate portion of the lenscapsule so as to stiffen the treated intermediate portion and improveaccommodation of the eye. The intermediate portion of the lens capsulemay be located between an optically used central portion of the lenscapsule and an elastic peripheral portion of the lens capsule connectedto zonules of the eye. The intermediate portion of the lens capsule maycomprise an intermediate portion of the anterior lens capsule, or anintermediate portion of the posterior lens capsule, or combinationsthereof. The stiffened intermediate portion of the lens capsule canimprove coupling of the elastic peripheral portion of the lens capsuleto the central portion of the lens capsule or an IOL at least partiallywithin the capsule, such that an amount of accommodation of theoptically used central portion of the natural lens or IOL can beincreased. The accommodation of the eye can be increased based on anincreased curvature of the optically used central portion of the naturallens or IOL, or based on an increased anterior axial movement of theoptically used central portion of the natural lens or IOL, orcombinations thereof, when the eye accommodates. In many embodiments,the thickness of the treated intermediate portion is maintainedsubstantially, such that the treated intermediate portion substantiallyresists and decreases radial movement so as to improve coupling andincrease radial forces of the peripheral portion of the lens capsule.The stiffened intermediate portion may comprise an annular shape profilesuch as a ring or annular oval extending substantially continuouslyaround the central portion so as to enclose the central portion, suchthat radial motion and stretching of the intermediate portion can bedecreased substantially. The stiffened intermediate portion comprisingthe annular shape profile can decrease circumferential stretching of theintermediate portion that may correspond to the radial movement of theintermediate portion, so as to decrease radial movement of theintermediate portion corresponding to the circumferential stretching ofthe intermediate portion.

The increased amount of accommodation may comprise one or more of anincreased radially inward force from the peripheral portion of the lenscapsule toward the central portion of the lens capsule, increasedanterior movement of the anterior lens capsule, increased movement ofthe lens anteriorly, increased curvature of the lens, an increasedcurvature of the central portion of the anterior lens capsule, or aprotrusion of the central portion of the anterior lens capsule havingthe increased curvature, or combinations thereof. As the radially inwardforce from the lens capsule to a lens disposed at least partially withinthe lens capsule can be increased, the lens may comprise the naturallens of the eye or an artificial lens such as an accommodating IOL. Whenused to increase accommodation of the natural lens of the eye, thetreatment can be applied to an anterior surface of the anterior lenscapsule so as to decrease invasiveness of the procedure and inhibitcataract formation. The treatment of the eye to stiffen the intermediateportion may comprise an agent to stiffen the intermediate portion suchas one or more of an energy, a substance to the applied to theintermediate portion, or a support coupled to the intermediate portion.The energy may comprise one or more of electromagnetic energy, RFenergy, microwave energy, light energy, UV light energy, visible lightenergy or infrared light energy to stiffen the portion. The agent maycomprise a substance applied to the portion so as to stiffen theportion, for example a stiffening adhesive, a tissue adhesive, or atissue fixative, or for example riboflavin, or a substance to inhibitnutrients to the portion. The amount of treatment may comprise enoughenergy or substance so as to stiffen the intermediate portion of thelens capsule without substantially shrinking the intermediate portion,such that far vision of the eye is substantially maintained. Thestiffening treatment may be combined with an additional treatment, suchas a softening treatment, so as to soften tissue of the lens capsuledisposed between the central portion and the stiffened intermediateportion so as to increase accommodation of the central portion.

In a first aspect, embodiments of the present invention provide a methodof treating an eye having a lens capsule and a lens, such as a naturallens or an IOL. The lens capsule has a central portion, a peripheralportion and an intermediate portion. The peripheral portion is connectedto zonules of the eye. The intermediate portion corresponds to alocation between the peripheral portion and the central portion. Theintermediate portion of the lens capsule is treated so as to stiffen theintermediate portion of the capsule and increase curvature or movementof at least a portion of the lens when the eye accommodates. Theincreased curvature can be combined with the increased movement toincrease an amount of accommodation of the eye.

The increased curvature of the lens may comprise an increased curvatureof a natural lens of the eye or an increased curvature of an IOL, andthe increased movement anteriorly may comprise an increased axialmovement of the natural lens of the eye or an increased axial movementof the IOL implanted in the eye.

In many embodiments, the increased curvature of the lens may comprise anincreased curvature of natural lens of the eye or an increased curvatureof an IOL, and the increased movement anteriorly may comprise anincreased movement of the natural lens of the eye or an increasedmovement of the IOL implanted in the eye.

In many embodiments, the intermediate portion is stiffened withoutshrinking substantially tissue of the intermediate portion such that farvision of the eye is maintained. The intermediate portion can bestiffened such that far vision of the eye is maintained to within about1 D and the accommodation is increased by at least about 1 D. In manyembodiments, the far vision refraction of the eye is maintained towithin about 0.5 D, and the accommodation is increased by about 1 D. Theintermediate portion of the capsule may be treated so as to maintain theoptical clarity and corresponding image quality of the intermediateportion when the intermediate portion is stiffened. Alternatively or incombination, the intermediate portion of the capsule may be treated soas to maintain substantially the thickness and corresponding distancevision of the intermediate portion of the lens capsule when stiffened.

In many embodiments, the capsule comprises an anterior capsule and theintermediate portion comprises an intermediate portion of the anteriorcapsule. The lens may comprise the natural lens of the eye, and thetreatment can be applied to the intermediate portion of the anteriorcapsule without penetration of the capsule.

In many embodiments, the central portion of the capsule is coupled tothe peripheral portion of the capsule with the stiffened intermediateportion such that the central portion is moved forward when the eyeaccommodates and peripheral portion moves inward. The central portion ofthe lens capsule may move anteriorly along an axis of the eye a firstamount and the intermediate portion may move anteriorly along the axis asecond amount, in which the first amount is greater than the secondamount such that the curvature of the central portion is increased whenthe eye accommodates.

In many embodiments, the capsule comprises a posterior capsule and theintermediate portion comprises an intermediate portion of the posteriorcapsule.

In many embodiments, treating the intermediate portion comprisesdelivering one or more of an energy or a substance to the intermediateportion. The energy may comprise one or more of thermal energy,mechanical energy, or electromagnetic energy. The electromagnetic energymay comprise RF energy, microwave energy, light energy, UV light energy,visible light energy or infrared light energy. The substance maycomprises one or more of an adhesive, a thermoreversible adhesive, asetae based adhesive, a curable adhesive, a tissue fixative, acrosslinker, a photo-sensitive crosslinker, or a substance to inhibitnutrients to the intermediate portion. The substance can be suitable fora chemical reaction, such as a photochemical reaction, and may comprisecross-linker, such as a photosensitive cross-linker.

In many embodiments, the light energy is transmitted through the corneaof the eye and absorbed with the intermediate portion to treat theintermediate portion.

In many embodiments, the one or more of the energy or the substance isdelivered to the intermediate portion of the capsule with a probe tipand the probe tip is introduced into an anterior chamber of the eyethrough an incision in an outer portion of a cornea.

In many embodiments, the substance comprises one or more of an adhesive,a thermoreversible adhesive, a setae based adhesive, a curable adhesive,a tissue fixative, riboflavin, or a substance to inhibit nutrients tothe intermediate portion.

In many embodiments, the one or more of the energy or the substance isdelivered to the intermediate portion of the capsule with a probe tipand the probe tip is introduced into an anterior chamber of the eyethrough an incision in an outer portion of a cornea.

In many embodiments, a capsulorhexis is performed to remove the centralportion of the capsule and place an intraocular lens within the capsule.

In many embodiments, the stiffened intermediate portion decreases radialmovement of the capsulorhexis edge such that radially inward force ofthe peripheral portion is increased by at least about 1 g when the eyeaccommodates.

The intermediate portion of the capsule can be treated before performingthe capsulorhexis to remove the central portion of the capsule, and atleast a portion of the stiffened intermediate portion of the capsuleremains so as to move the peripheral portion inward when the eyeaccommodates with the intraocular lens.

In many embodiments, the stiffened portion supports the peripheralportion such that the peripheral portion moves the intraocular lensforward with a force of at least about 3 g.

In many embodiments, the lens capsule is retreated with a secondtreatment to stiffen the lens capsule at least about one day after thetreatment to increase the amount of accommodation of the eye.

In many embodiments, the lens with is treated a softening treatmentlocated inward of the treatment to stiffen the intermediate portioncapsule so as to couple the stiffened intermediate portion to thesoftened tissue to increase the amount of accommodation of the eye.

In another aspect, embodiments of the present invention provide andapparatus to treat an eye. The eye has a lens comprising a capsule. Theapparatus comprises a delivery device to couple to an intermediateportion the capsule to deliver one or more of an energy or a substanceto the intermediate portion. Circuitry is coupled to the delivery deviceto deliver the one or more of the energy or the substance to the eye tostiffen the intermediate portion.

In many embodiments, the circuitry is configured to deliver the one ormore of the energy or the substance to the intermediate tissue with atreatment profile so as to stiffen the tissue without shrinkingsubstantially tissue of the intermediate portion.

In many embodiments, the circuitry comprises a processor having computerreadable memory, the computer readable memory having instructions storedthereon to treat the tissue with the treatment profile.

In another aspect, embodiments provide an apparatus to treat an eye, inwhich the eye has a lens and a lens capsule. The lens capsule has anintermediate portion extending between a central portion of the lenscapsule and a peripheral portion of the lens capsule. The apparatuscomprises a deflectable structure to couple to the intermediate portionthe lens capsule to deliver an agent to the intermediate portion so asto stiffen the intermediate portion, and the deflectable structurecomprises an amount of the agent sufficient to stiffen the intermediateportion.

In many embodiments, the deflectable structure is sized to pass throughan incision of no more than about 2 mm, and the deflectable structurecomprise a first configuration to provide a narrow profile for insertionthrough the incision and a second configuration to provide a wideprofile for placement on the intermediate portion of the capsule. Thefirst configuration may comprise one or more of a folded or rotatedconfiguration for passage through the incision and the secondconfiguration may comprise one or more of an unfolded or a c-shapedconfiguration for placement on the intermediate portion of the capsule.

In another aspect, embodiments provide a method of treating an eyehaving a lens and a lens capsule. The capsule has a central portion anda peripheral portion connected to zonules of the eye. An adhesive isapplied to the intermediate portion of the capsule to stiffen theintermediate portion to increase one or more of curvature or movement ofthe lens when the eye accommodates. The intermediate portion is locatedbetween the central portion and the peripheral portion.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A shows accommodation of an eye, suitable for incorporation inaccordance with embodiments of the present invention;

FIG. 1B shows structures of the eye as in FIG. 1A;

FIG. 1C shows elastic stretching of the lens capsule of the eye as inFIGS. 1A and 1B, suitable for incorporation in accordance withembodiments as described herein;

FIG. 2A shows an eye having an intermediate portion of the anterior lenscapsule and an intermediate portion of the posterior lens capsulestiffened to increase accommodation, in accordance with embodiments ofthe present invention;

FIG. 2A-1 shows a stiffness profile of the lens capsule, in accordancewith embodiments;

FIG. 2A-2 shows a protrusion and increased curvature of the anteriorlens capsule when the eye accommodates with intermediate portion of thelens capsule stiffened to increase accommodation, in accordance withembodiments of the present invention;

FIG. 2A-3 shows the elevation, diameter and increased optical power ofthe protrusion as in FIG. 2A-2 when the eye accommodates;

FIG. 2A-4 shows the optical power of the central portion of the lenscorresponding to the protrusion of the central portion of the lenscapsule when the eye accommodates, in accordance with embodiments of thepresent invention;

FIG. 2B shows a side view an eye having an intermediate portion of theanterior lens capsule stiffened to increase accommodation, in accordancewith embodiments of the present invention;

FIG. 2C shows a front view the eye having an intermediate portion of theanterior lens capsule stiffened to increase accommodation as in FIG. 2B;

FIGS. 2D and 2E show side and front views, respectively, of the eyehaving the support coupled to the intermediate portion of the eye toincrease elastic stretching of the lens capsule to the decreasepresbyopia as in FIGS. 2B and 2C;

FIG. 2F shows the support comprising an oval shape to correctastigmatism of the eye, in accordance with embodiments.

FIG. 3A shows a side view the eye having an accommodative IOL positionedsubstantially within a lens capsule having the intermediate portionstiffened to increase accommodation, in accordance with embodiments ofthe present invention;

FIG. 4A shows a side view of treatment of the eye to stiffen theintermediate portion of the lens capsule with a probe, in accordancewith embodiments of the present invention;

FIG. 4B shows a side view treatment of the eye to stiffen theintermediate portion of the lens capsule with a light beam, inaccordance with embodiments of the present invention;

FIG. 4C shows a side view of treatment of the eye with a light beam tosoften a portion of the lens capsule located between the intermediateportion and the central portion, in accordance with embodiments of thepresent invention;

FIG. 4D shows a front view of softening treatment of the portion of theeye as in FIG. 4C;

FIG. 4E shows the treatment as in FIGS. 4C and 4D located within thecapsule to inhibit penetration of the capsule;

FIG. 4F shows the retreatment of the capsule, in accordance withembodiments;

FIG. 5A shows a top view of a structure to apply an agent to theintermediate portion of the lens capsule, in accordance with embodimentsof the present invention;

FIG. 5B shows a top view of the structure as in FIG. 5A folded forinsertion through an incision, in accordance with embodiments of thepresent invention;

FIGS. 5B1 and 5B2 show the structure comprising an expanded wide profileconfiguration, and narrow profile configuration for insertion into theeye through an incision in the cornea, respectively, in accordance withembodiments;

FIG. 5B3 shows a narrow profile configuration for insertion into the eyethrough the incision with rotation of the structure as shown in FIG.5B1;

FIG. 5C shows a stiffening support coupled to the intermediate portionof the capsule to stiffen the intermediate portion with the support, inaccordance with embodiments of the present invention;

FIG. 6A shows an apparatus to apply a treatment profile to stiffen theintermediate portion of the lens capsule, in accordance with embodimentsof the present invention;

FIG. 6B shows the treatment profile to stiffen the intermediate portionof the lens capsule with the apparatus as in FIG. 6A, in accordance withembodiments of the present invention;

FIG. 7 shows a graph of accommodative force of the peripheral portion ofthe lens with stiffening of the intermediate portion based oncalculations.

DETAILED DESCRIPTION OF THE INVENTION

Embodiments of the present invention as described herein can be used inmany ways to improve accommodation of the presbyopic eye such thataccommodation is increased to at least some extent. The embodiments asdescribed herein can be used to treat presbyopia with an otherwisehealthy eye, in a non-invasive or minimally invasive manner, such thatthe accommodation of the natural lens of the eye is enhanced. Theembodiments as described herein can also be used in conjunction withIOLs such that the amount of accommodation with the IOL can beincreased. The treatment of the capsular tissue can increase radiallyinward force to an IOL from about 1 gram (hereinafter “g”) to at leastabout 3 g, for example at least about 4 g, in exemplary embodiments atleast about 6 g, so as to provide corresponding improvement inaccommodation, for example at least about a two fold increase, forexample about a three fold increase, in the amount of accommodation whencombined with a commercially available accommodating IOL.

The embodiments as described herein can be used in combination withenhancements to the crystalline lens or with the cornea, or with aphakic IOL or intracorneal inlays, for example. The treatment maycomprise treatment of the capsule such that the other portions of thelens remain substantially untreated. Alternatively, the crystalline lensmay be softened with a laser in conjunction with treating the capsule.Embodiments as described herein can also be used with accommodating IOLsso as to increase substantially the amount accommodation of theimplanted accommodating IOLs. The accommodating IOL may comprise adeformable IOL that can provide increased curvature when the eyeaccommodates, or an IOL in which the treatment increases axial movementof the substantially rigid lens when the eye accommodates, orcombinations thereof. For example the treatment can be combined with anIOL having a substantially rigid lens in which the treatment increasesaxial movement of the lens.

The stiffening of the capsule to increase the amount of accommodationcan be done in many ways. Stiffening of the capsule can be done toincrease the power change by creating stiffening rings and/or regionsthat can amplify the optical power change, for example by increasingcurvature of the lens capsule. The capsule can be stiffened with use ofmethods such as laser, mechanical, electrical (radiofrequency) orchemical.

Alternatively or in combination with increasing an amount ofaccommodation of the eye, the stiffening treatment as described hereincan be used to treat astigmatism of the eye, and may decrease sphericalaberration of the eye, for example with increased accommodation of theeye.

As used herein, stiffness encompasses a relationship between stress andstrain. The relationship can be linear, or non-linear, or combinationsthereof, for example.

FIG. 1A shows accommodation of an eye 10. The eye 10 has a cornea 12 anda lens 20. The cornea and lens focus light on a retina 15 such that thepatient perceives the image with the light sensitive tissue of theretina. When the image on the retina is focused, the image appears sharpto the patient. However, when the image is out of focus, the imageappears blurred. The lens 20 of the eye accommodates to the distance ofthe object viewed such that the image of the object is focused on theretina and remains sharp to the patient. For far vision, the lens 20 ofeye 10 relaxes to focus on a far point. The far point can be severalmeters away, such that the vergence of the target is approximately 0Diopters. The near point can be located at a distance suitable forreading, for example, and can be about 12 inches (⅓ meter) from the eye,for example, such that the vergence of the object is about 3 Diopters.The accommodation range corresponds to the range over which the eye canaccommodate so as to bring the viewed object into focus. The amount ofaccommodation can be expressed with the optical power used to bring anobject into focus, and the optical power can be expressed in units ofDiopters (hereinafter “D), to bring the object into focus. For anemmetropic eye capable of focusing on an object at a far distance ofabout 10 meters and an object at a near distance of about ⅓ of a meterfrom the patient, the amount of accommodation expressed as a range ofoptical power is at least about 3 D.

FIG. 1B shows structures of the eye as in FIG. 1A. The eye 10 comprisescornea 12, an anterior chamber 14 and an iris 16. The cornea 12 hasabout two thirds of the optical power of the eye, and is opticallycoupled to the lens 20 so as to focus light on the retina of the eye.The eye 10 has a sclera 13 comprising the visible white portion of theeye. The iris 16 can define a pupil 18 of the eye. The eye may comprisea visual axis or optical axis 11, for example a line of sightcorresponding to a center of the pupil. The iris 16 may contractslightly when the eye accommodates. The lens 20 comprises a capsule 22,a cortex 24 and a nucleus 26. The eye has ciliary muscles 32 connectedto ciliary zonules 30. The ciliary zonules 30 are connected to lenscapsule 22 at a peripheral portion 22P of the lens capsule.

Description of the eye 10 suitable for combination in accordance withthe embodiments as described herein with reference to FIG. 1A and FIG.1B is at least partially described in one or more the followingpublications by Adrian Glasser:

-   Glasser, A. (2010) Accommodation. In: Darlene A. Dartt, editor.    Encyclopedia of Eye, Vol I. Oxford: Academic Press; p. 8-17.-   Glasser, A. (2004) Physiology of Accommodation and Presbyopia, In    Surgery for Hyperopia. Ed. Neil Sher, pp. 11-21, SLACK, Inc.    Thorofare, N.J.-   Glasser, A. (2003) The Helmholtz Mechanism of Accommodation. In    Current Research in Eye Surgery Technology (CREST). Eds. K.    Tsubota, B. S. Boxer Wachler, D. T. Azar, D. Koch. pp. 27-47. Marcel    Dekker, Inc., New York.-   Glasser, A. and Kaufman, P. L. (2002) Accommodation and Presbyopia.    In Adler's Physiology of the Eye. 10th Edition. Eds Kaufman P. L.    and Alm, A. pp. 195-233.-   Mosby, S I. Louis.

During accommodation, the lens and ciliary components of the eye adjustto bring an object into focus. When the eye has a “relaxed”configuration for far vision, the ciliary muscle 32 of the eye isrelaxed such that zonules 30 pull the lens capsule 22 outward. When theeye accommodates for near vision, the ciliary muscle 32 contracts suchthat zonules 30 allow the lens peripheral portion 22P of the lenscapsule to move radially inward with a radially inward force 40. Whenthe peripheral portion 22P moves radially inward, the front portion ofthe lens capsule moves forward with anterior movement 42 such that theanterior optical surface of the lens moves forward so as to bring theimage of the near object into focus on the retina. In addition, thecurvature of the anterior surface of the lens 20 can increase when thefront portion of the lens capsule moves forward so as to increase theoptical power of the lens 20 and bring the image of the object intofocus on the retina. When the peripheral portion 22P moves radiallyoutward, the front portion of the lens capsule moves with posteriormovement 43 such that the anterior optical surface of the lens movesposteriorly and decreases curvature so as to bring the image of the farobject into focus on the retina.

With presbyopia, the inner components of the lens such as the cortex 24may stiffen, such that the amount of accommodation decreases. The amountof anterior movement 42 of lens 22 and the amount correspondingcurvature change decreases such that the eye is no longer capable ofbringing both near and far objects into focus with accommodation.

FIG. 1C shows elastic stretching of the lens capsule 22 of the eye as inFIGS. 1A and 1B, suitable for incorporation in accordance withembodiments. The lens of the eye comprises a first relaxed configuration20A of the lens capsule for accommodation, and a second stretchedconfiguration 20S of the lens capsule for far vision. The first relaxedconfiguration 20A corresponds to constriction of the ciliary muscle 32such that tension on zonules 30 is decreased such that and the lens canrelax and move forward with anterior movement 42. The second stretchedconfiguration 20S corresponds to radially outward stretching of the lenswhen the ciliary muscles of the eye relax and the zonules attached tothe peripheral portion 20P stretch the lens capsule and move the lensradially outward, such that and the lens can stretch and move withposterior movement 43. The correspondence of locations of lens 20 forthe relaxed lens configuration 20A for accommodation and the stretchedlens configuration 20S are shown with arrows 46.

The lens 20 stretches when the ciliary muscles relax such that thecapsule is stretched radially outward. The relaxed lens configuration20A for accommodation for near vision has a central portion 22C of thelens capsule 22, an intermediate portion 22IA, and a peripheral portion22AP. The relaxed configuration 20A for accommodation comprises thecentral portion 22CA located along axis 11, the intermediate portion22IA located a radial distance 22RIA from axis 11 and the peripheralportion 22PA located a radial distance 22PRA from axis 11. The relaxedconfiguration 20A comprises an outer portion 22OA extending from theintermediate portion 22IA to the peripheral portion 22PA with a distance22ODA. The central portion 22CA has a curvature 22CAC when the lenscomprises the relaxed configuration for accommodation.

The stretched lens configuration 20S for far vision has a centralportion 22CS of the lens capsule 22, an intermediate portion 22IS, and aperipheral portion 22AS. The stretched lens configuration 20S for farvision comprises the central portion 22CS located along axis 11, theintermediate portion 22IS located a radial distance 22RIS from axis 11and the peripheral portion 22PS located a radial distance 22PRS fromaxis 11. The stretched configuration 20S comprises an outer portion 22OSextending from the intermediate portion 22IS to the peripheral portion22PS with a distance 22ODS. The central portion 22CS has a curvature22CSC when the lens comprises the stretched configuration for farvision.

The stretching of lens capsule 22 with lens configuration 20S can storeenergy and provide an increased amount of radially inward force 40, soas move the anterior capsule forward with anterior movement 42. Thestretching of lens capsule 42 extends from axis 11 to peripheral portion22P. The radial distance 22PRS is greater than the radial distance22PRA, corresponding to stretching of the central portion 22C, theintermediate portion 22I, the outer portion, and the peripheral portion22P. The radial distance 22RIS is greater than the radial distance 22RIAcorresponding to stretching of the intermediate portion 22I and centralportion 22C. The radial distance 22ODA is less than the radial distance22ODS corresponding to stretching of the outer portion 22O locatedbetween intermediate portion 22I and peripheral portion 22P. Althoughthe stretched components of the lens capsule can move the peripheralportion 22P radially inward with the force 40, the presbyopic lens canbe stiffer than the non-presbyopic lens such that the anterior movement42 and the corresponding curvature change may not be enough to provideaccommodation.

FIG. 2A shows a side view of eye 10 having an intermediate portion 22Iof the anterior lens capsule and an intermediate portion of theposterior lens capsule stiffened so as to increase accommodation. Anintermediate portion 22I of the lens capsule 20 is stiffened withtreatment so as to increase accommodation of the patient. Theintermediate portion 22I is disposed between an inner central portion22C and a peripheral portion 22P attached to the zonules. Theintermediate portion 22I may extend completely around the centralportion 22C so as to define the central portion 22C with the innerboundary of the intermediate portion 22I. The intermediate portion 22Imay comprise a ring, or annular oval, extending around the centralportion so as to enclose the central portion. The eye comprises ananterior orientation A toward the cornea and a posterior orientation Ptoward the retina.

The inner central optical portion 22C comprises an optically usefulportion of the lens capsule 22, and corresponds to light transmittedthrough the pupil of the eye. The intermediate portion 22I can belocated away from the central portion 22C such that the central portionremains optically clear and substantially free from aberrations andlight scatter. The intermediate portion may correspond to a portion ofthe capsule covered by the pupil, for example in bright light. In manyembodiments, the intermediate portion is covered by the pupil in dimillumination, for example, such that the patient can receive the benefitof increased accommodation when reading in dim light or viewing objectsin dim light for example. The intermediate portion may comprise anintermediate portion of the anterior capsule, or an intermediate portionof the posterior capsule, or both, for example.

The thickness of the treated intermediate portion 22I can be maintainedsubstantially, such that the treated intermediate portion substantiallyresists and decreases radial movement. The resistance and decreasedradial movement can improve coupling and increase radial forces of theperipheral portion of the lens capsule to the central portion of thelens capsule. As radial stretching of the intermediate portion 22I cancorrespond to an increase circumference of the stretched intermediateportion, the stiffened intermediate portion may comprise an annularshape such as a ring or oval extending circumferentially andsubstantially continuously around the central portion, so as to enclosethe central portion the such that decreased circumferential stretchingof the intermediate portion can decrease the radial motion andstretching of the intermediate portion.

The stiffened intermediate portion of the capsule 22I can increaseaccommodation of the eye 10 in many ways. The accommodation can beincreased with one or more of increased radially inward force 40 of thelens capsule, increase anterior movement 42 of the lens capsule,increased curvature 22AC of the lens capsule, or increased curvature22CPC of the central portion comprising a protrusion 22CP (FIG. 2A-3),or combinations thereof. With the stiffened portion 22I, the radiallyinward force 40 can be increased when the ciliary muscles of the eyecontract and the zonules allow the peripheral portion of the capsule tomove inward. The increased radially inward force 40 can provideincreased amount of the anterior movement 42 of the lens capsule. Theincreased anterior movement 42 of the lens may provide an increasedcurvature 22CAC of the central portion 22CA when the lens accommodatesso as to increase accommodation of the eye. Also, the increased anteriormovement 42 of the lens capsule may provide increased accommodationbased at least partially on an increased distance from the centralportion 22C of the lens capsule to the retina. Alternatively or incombination, the increased forward axial movement 42 may provideprotrusion 22CP having increased curvature 22CPC when the eyeaccommodates as described herein with reference to FIG. 2A-3, forexample.

FIG. 2A-1 shows a stiffness profile 22SP of lens capsule 22C, inaccordance with embodiments. The stiffness profile 22SP is shown inradial coordinates extending from a central value of zero near a centerof the lens capsule to the peripheral portion 22P of the lens capsule.The stiffness profile 22SP may correspond to a percent stiffness of thelens capsule after treatment to the stiffness of the lens capsule 22Cprior to treatment. The central portion 22C and the outer portion 22Omay each have a substantially unchanged stiffness before and aftertreatment corresponding to a post-treatment stiffness of one hundredpercent. The stiffness profile 22SP of the intermediate portion 22I maycorrespond to a graded change in the amount of stiffness, such that thestiffness profile 22SP comprises a peak stiffness. The stiffness profile22SP corresponding to intermediate portion 22I can extend from the peakto the untreated portions with a graded amounts of relative stiffness.

The stiffening treatment as described herein can increase the modulus,for example the Young's modulus of the lens capsule of the intermediateportion 22I. The lens capsule may comprise a Young's modulus within arange from about 1.5 mN/mm2 to about 3 mN/mm2, for example. (See WeeberH A., Martin H. The Role of the Capsular Bag in Accommodation. In:Guthoff R, Ludwig K, eds. Current Aspects of Human Accommodation II.Heidelberg: Kaden Verlag; 2003). Although the material properties of thelens capsule can be at least somewhat non-linear and the Young's modulusof the lens capsule can vary with age, a person of ordinary skill in theart can determine empirically the thickness and corresponding modulusbased on the teachings described herein, so as to provide stiffeningtreatment to the intermediate portion 22I and increased accommodation.

The intermediate portion of the lens capsule can be stiffened an amountsufficient to increase accommodation, for example increased by at leastabout 50%. In many embodiments, the stiffening of the lens capsule maycomprise at least about 100% stiffening so as to increase accommodationof the eye. The stiffening of the intermediate portion of the lenscapsule can be achieved without substantially shrinking the treatedtissue, so as to decrease changes in far vision refraction of the eye.The non-substantial shrinkage of the capsule may corresponds to a changein distance refraction of no more than about 1 D. The treatment of thelens capsule can maintain thickness of the lens capsule when stiffened,such that the stiffened intermediate portion can resist radial movementand decrease movement radially so as to improve coupling increase radialforces of the peripheral portion of the lens capsule coupled to the lensdisposed at least partially within the capsule. As the amount of radialforce to stretch the lens capsule radially outward and the correspondingradially inward force available to move the lens during accommodationcan be related to the thickness of the lens capsule and the modulus ofthe lens capsule, substantially maintaining the thickness of the lenscapsule to within about +/−30% of the thickness prior to treatment whenthe lens capsule is stiffened can improve coupling and increase radialforces of the peripheral portion to the lens components located at leastpartially within the lens capsule and increase radially inward forces tothe lens components. In many embodiments the thickness of the stiffenedtissue can be maintained to within about +/−20%, for example to withinabout +/−15%. The treated intermediate portion 22I may comprise asubstantially continuous treatment region extending substantiallyaround, for example completely around, the central portion 22C so as toenclose the central portion 22C within the capsular treatment regioncomprising intermediate portion 22I.

As the shrinkage of the treated intermediate portion of the lens capsulemay correspond to nearsightedness, amounts of shrinkage corresponding toabout 1 D of induced nearsightedness in conjunction with about a 1 Dincrease in accommodation can produce a successfully result. Forexample, a patient who is emmetropic prior to surgery that undergoestreatment and becomes −1 D nearsighted with far vision and canaccommodate 1 D can bring an object that is about ½ meter away intosharp focus.

FIG. 2A-2 shows increased curvature of the anterior lens capsule whenthe eye accommodates with the intermediate portion of the lens capsulestiffened to increase accommodation. The central portion of the lenscapsule may comprise a first curvature profile 22C1 when the eye doesnot accommodate, for example when the lens capsule is stretched asdescribed herein. The second curvature profile 22C2 may correspond tothe elevation profile of a protrusion 22CP of the central portion whenthe eye accommodates with the intermediate portion stiffened, forexample when the peripheral and outer portions of the lens capsule arenot stretched and the eye accommodates. When the eye having theintermediate portion stiffened accommodates with radially inwardmovement of the peripheral portion 22P, the stiffened intermediateportion 22I can direct the curvature change to the non-stiffened centralportion 22C, such that the central portion 22P moves anteriorly agreater amount than intermediate portion 22I. This anterior movement ofthe central portion 22P an amount greater than intermediate portion 22Imay correspond to a bulging of the central portion 22P so as to provideprotrusion 22CP and increase curvature of the central portion 22P. Thecentral portion having protrusion 22CP has the increased change incurvature corresponding to increased optical power of the centralportion 22C.

FIG. 2A-3 shows the diameter, elevation and increased optical powercorresponding to the curvature 22CPC of the protrusion 22CB when the eyeaccommodates with the stiffened intermediate portion 22I of the lenscapsule. The lens 20 has a configuration 20A for accommodation with theoutward tension of the zonules decreased such that lens capsule relaxesand the peripheral portion 22P has moved radially inward. The protrusion22CP of the central portion 22C has an elevation relative to a referencesurface profile comprising the surface of the central portion 22CA whenthe eye accommodates naturally as described above without the stiffeningtreatment of the intermediate portion 201. The elevation of the centralportion 22C comprising protrusion 22CP may comprise an inflection 22CIextending around the protrusion 22CP where the curvature of the lenscapsule may change abruptly and the stiffened intermediate portion 22Icouples the central portion 22C. Alternatively to the abrupt change incurvature, the curvature near inflection 22CI can increase graduallywith a graded transition profile such that the central portion 22Ccomprises a prolate elevation profile so as to correct sphericalaberration of the eye.

The boundary of central portion 22CP and intermediate portion 22I maycomprise a smooth graded change in curvature and profile, for examplewhen the intermediate portion receives treatment so as to provide thegraded stiffness profile. The graded stiffness profile may provide thecurvature near inflection 22CI that increases gradually such that thecentral portion 22CP comprises the prolate elevation profile

The increased elevation and curvature of the central portion relative tothe peripheral portion can increase the optical power of the centralportion substantially. The lens has an index of refraction of about 1.45and the aqueous humor has an index of refraction of about 1.33, suchthat the curvature of the central portion 22C provides optical power.The optical power of the protrusion can be determined based on thecurvature corresponding to the height and diameter of the protrusion22CP.

FIG. 2A-4 shows the increased optical power corresponding to curvature22CPC for varying diameters and elevations of the protrusion 22CP whenthe eye accommodates. The elevation of the protrusion is proportional tothe optical power in Diopters (D) and to the square of the protrusiondimension across, for example a diameter across for a sphericalprotrusion. The diameters and corresponding elevations so as to providecurvature changes corresponding 1 D, 2 D, 3 D and 4 D of accommodationare shown in Table 1. For a curvature corresponding to the 1 Dprotrusion having a diameter of 5 mm, the elevation is about 35 um. Fora curvature corresponding to a 2 D protrusion having the 5 mm diameter,the elevation is about 70 um. A comparison of the elevation of the 1 Dprotrusion to the 2 D protrusion shows the approximately linearrelationship of optical power to protrusion elevation. For a 1 Dprotrusion having a diameter of about 3 mm, the elevation is about 12um. For the 1 D protrusion having a diameter of about 6 mm the elevationis about 50 um. A comparison of the 1 D protrusion having the diameterof 3 mm to the 1 D protrusion having the diameter of about 6 mm showsthat the elevation is approximately proportional to the square of thediameter. Based on the dimensions shown, a protrusion 22CP having anexemplary 4 mm diameter and a height of about 45 um can have anincreased curvature so as to provide about 2 D of additionalaccommodative optical power.

TABLE I Diameters and corresponding elevations to provide curvaturechanges corresponding 1 D, 2 D, 3 D and 4 D of increased accommodation.Diameter Elevation Elevation Elevation Elevation mm @1D @2D @3D @4D 0 00 0 0 0.5 0.347 0.694 1.04 1.39 1 1.39 2.78 4.17 5.56 1.5 3.13 6.25 9.3812.5 2 5.56 11.1 16.7 22.2 2.5 8.68 17.4 26.0 34.7 3 12.5 25 37.5 50 3.517.0 34.0 51.0 68.1 4 22.2 44.4 66.7 88.9 4.5 28.1 56.3 84.4 112.5 534.7 69.4 104.1 138.9 5.5 42.0 84.0 126.0 168.1 6 50 100 150 200 6.558.6 117.4 176.0 234.7 7 68.1 136.1 204.1 272.2

The additional optical power provided by protrusion 22CP can be combinedwith anterior movement of the central portion 22C and the intermediateportion 22I, so as to further increase the amount of accommodativeoptical power when protrusion 22CP increases curvature of the centralportion 22C. For example, increased stretching of the peripheral andouter portions of the lens capsule can be combined with the protrusion22CP and the anterior movement of the intermediate portion 22I andcentral portion 22C, so as to provide greater than about 2 D ofaccommodative optical power when the protrusion 22P provides about 2 Dof accommodative optical power.

FIG. 2B shows a side view of the eye 10 having intermediate portion 22Iof the anterior lens capsule stiffened to increase accommodation. Thisstiffening of the anterior capsule can be less invasive than stiffeningthe posterior capsule, for example, and can be used in many embodimentsthat comprise increasing the amount of accommodation of natural lens ofthe eye, for example.

FIG. 2C shows a front view the eye having intermediate portion 22I ofthe anterior lens capsule stiffened to increase accommodation as in FIG.2B. The central portion 22C may comprise a distance across such as adiameter. The distance across the central portion 22C can be defined bythe treatment of the intermediate portion and can be within a range fromabout 1.5 mm to about 6 mm, for example. The dimensions of the centralportion 22C may correspond to dimensions of the pupil, for examplewithin a range of about 2 mm to about 6 mm, for example within a rangefrom about 3 mm to about 5 mm, so as to correspond to dimensions of thepresbyopic pupil. The intermediate portion 22I comprises a distanceacross, for example an inner annular diameter and an outer annulardiameter. The inner annular diameter may correspond to the size of thecentral portion 22C. The outer annular dimension of the intermediateportion 22I may correspond to an outer diameter of treatment, forexample. The outer annular dimension may correspond to a dimension ofthe dilated pupil with cycloplegia, for example, such that theintermediate portion can be accessed readily during surgery, for examplewhen the pupil is dilated during surgery. The peripheral portion 22P maycomprise a substantially untreated portion of the lens capsule coupledto the zonules of the eye such that the peripheral portion can stretchelastically. Based on the teachings described herein, a person ofordinary skill in the art can determine dimensions of the intermediateportion so as to increase accommodation and decrease presbyopia with thenatural lens of the eye, for example. The anterior capsule when treatedmay comprise similar dimensions, for example.

FIGS. 2D and 2E show side and front views, respectively, of the eyehaving the stiffened intermediate portion of the capsule to increaseelastic stretching of the lens capsule to the decrease presbyopia. Theintermediate portion 22I of the lens capsule can be stiffened such thatthe strain of the intermediate portion corresponds to the relaxedcapsule during accommodation so as to increase stretching of the outerportion 22O of the lens capsule when the ciliary muscle relaxes and thecapsule is stretched with the zonules.

The increased stretching of lens capsule 22 with lens configuration 20Scan store energy and provide an increased radially inward force asindicated by arrows 40, so as to increase curvature and move theanterior capsule forward as indicated with arrow 42. The increasedstretching of lens capsule 42 corresponds to increased stretching ofouter portion 22O of the capsule between the stiffened intermediateportion 22I and the peripheral portion 22P coupled to the zonules. Theradial distance 22RIS is similar to radial distance 22RIA correspondingto no substantial increased stretching of the intermediate portion 22Iand central portion 22C. The radial distance 22ODA is less than theradial distance 22ODS corresponding to stretching of the outer portion22O located between intermediate portion 22I and peripheral portion 22P.As the peripheral portion 22P of the lens may be pulled that radialdistance 22PRS corresponds substantially to the eye without thestiffening treatment as shown above, the radial stretching distance22ODS can be substantially greater for the eye with the stiffenedintermediate portion 22I.

The intermediate portion of the lens capsule can be treated with amountsof strain corresponding to the relaxed lens capsule duringaccommodation, or amounts of strain corresponding to stretching of thelens capsule when the ciliary muscle of the eye relaxes for far vision,and amounts in between. For example, with capsulorhexis, it can behelpful to stiffen the tissue around the edge of the capsulorhexisincision when the eye is dilated and corresponds to a stretched lenscapsule. With the natural crystalline lens of the eye, the amount ofstrain of the intermediate portion 22I and the central portion 22C canbe related to the elevation of protrusion 22CP. The decreased radialmovement and decreased circumferential stretching of intermediateportion 22I can define an outer boundary of protrusion 22CP andencourage formation of protrusion 22CP.

The curvature profile elevation data and figures as described hereinshow that presbyopia can be treated with an appropriately sizedintermediate portion 22I so as to produce a protrusion to treatpresbyopia, and that the protrusion can be used in combination withadditional components of accommodation, such as movement anteriorly ofthe intermediate portion 22I and the central portion 22C when the eyeaccommodates, and radially inward elastic force and radially inwardmovement of the peripheral portion of the lens capsule. The elasticperipheral and outer portions of the lens capsule can move theintermediate and central portions of the lens capsule anteriorly whenthe eye accommodates, and the elastic peripheral and outer portions ofthe lens capsule can provide radially inward force and radially inwardmovement of the peripheral portion of the lens capsule to move theintermediate portion 22I and the peripheral portion 22P anteriorly. Theintermediate portion 22I can be stiffened with an amount of strain toprovide appropriate far vision refraction and increased accommodation.The amount of strain of the stiffened intermediate portion maycorrespond to the stretched lens capsule for far vision, thenon-stretched accommodating lens capsule, or amounts of strain inbetween corresponding to intermediate vision. In many embodiments, theintermediate portion 22I is stiffened when the eye does not accommodateand the lens capsule is stretched, for example when dilated duringsurgery, such that the intermediate portion 22I and the central portion22C comprise a curvature and strain corresponding to thenon-accommodating stretched lens capsule for far vision of the eye.Alternatively, the intermediate portion 22I can be stiffened withamounts of strain corresponding substantially to the non-stretchedcapsule when the eye accommodates, for example, such that theintermediate portion 22I and the central portion 22C comprise acurvature and strain corresponding to the non-stretched accommodatinglens capsule.

FIG. 2F shows a view along the axis 11 of the stiffened intermediateportion 22I comprising an oval shape to correct astigmatism of the eye.The oval shape profile may comprise one or more of an elliptical shape,a lentoid shape, or an asymmetrical elliptical shape, extendingsubstantially around central portion 22C such that protrusion 22CPcomprises a substantially tonic shape when the eye accommodates to as tocorrect the astigmatism of the eye. The astigmatism of the eye maycomprise lenticular astigmatism or corneal astigmatism. For example, theastigmatism may comprise corneal with the rule astigmatism correspondingto a toric corneal shape having a steeper corneal curvature along asubstantially vertical axis 12C and a flatter corneal curvature along asubstantially horizontal axis 12B, such that a depth contour plot of thetonic cornea shows ellipses such as ellipse 12A having a short axisextending along vertical axis 12C and long axis 12B perpendicularvertical axis 12C. Merely by way of example, the curvature of the corneaalong axis 12B can correspond to an optical power of about 43 D, and thecurvature of the cornea along axis 12C can correspond to an opticalpower of about 44 D, for example.

The long dimension of the oval intermediate portion 22I can be alignedwith the astigmatism of the eye such as with the rule astigmatism, so asto correct the vision of the eye. For example, the long dimension of theoval intermediate portion 22I can be aligned with the steepersubstantially vertical axis 12C, and the shorter dimension of the ovalintermediate portion 22I can be aligned with the flatter substantiallyhorizontal axis 12B. The oval protrusion 23P can have a ratio of thelong axis to the short axis so as to correct the astigmatism of the eyewhen the lens capsule is relaxed with ciliary muscle contraction and theeye accommodates for near vision, or when the lens capsule is stretchedwith the zonules and the ciliary muscle is relaxed for far vision.

The stiffened oval intermediate portion 22I can induce astigmatism ofthe lens with tonic protrusion 22CP so as to correct the astigmatism ofthe eye. The oval intermediate portion 22I coupled to annular ovalsupport 100 comprises a shorter inner dimension 112A and a shorter outerdimension 114B. The oval stiffened intermediate portion 22I comprises anelongate inner dimension 112B and an elongate outer dimension 114B. Theshorter inner dimension 112A and the elongate inner dimension 114A candefine the oval outer boundary of the central portion 22C, such that thecentral portion 22C comprises an oval shape profile having one or moreof an elliptical shape profile, a lentoid shape profile, or anasymmetrical elliptical shape profile. In many embodiments, the ovalshape profile corresponds to a tonic shape of the protrusion 22CP whenthe eye accommodates. When the lens capsule moves anteriorly withaccommodation of the lens capsule such that central portion 22Ccomprises protrusion 22CP, the curvature change of the lens capsule canbe related to the inner dimensions across the intermediate portion suchas shorter inner dimension 112A and elongate inner dimension 112B. Theshorter dimension 112A corresponds to a steeper curvature change of thelens capsule when the central portion moves anteriorly, and the elongatedimension 112B corresponds to a less steep change in curvature when thelens capsule moves anteriorly. The flatter curvature change along theaxis of the elongate dimension 112B of the oval can correct the with therule astigmatism along the vertical axis 12C.

The curvature 22CPC and corresponding elevation profile of theprotrusion 22CP can be combined with the shorter inner dimension 112Aand the elongate inner dimension 112B so as to determine the amount ofoptical correction of the protrusion. Alternatively or in combination,the ratio of the shorter dimension to the longer dimension and theelevation of the protrusion 23C can be used to determine the opticalcorrection of the tonic protrusion. For example, a patient can havecorneal astigmatism with keratometer readings of about 43 D along anaxis 180 of degrees and 44 D along an axis of 90 degrees correspondingto a refraction of the eye of about 0 D sphere-1.0 cylinder along anaxis of 180 degrees. The dimensions of the short dimension and the longdimension of the oval can be sized to induce astigmatism of the lens tocorrect the astigmatism of the eye when the eye accommodates. Forexample the long dimension and the short dimension of the oval supportcan be sized such that the long dimension corresponds to about +1 D ofoptical power along axis 12C and the short dimension of the ovalcorresponds to about +2 D of optical power along axis 12B when the eyeaccommodates, such that the refraction of the eye with accommodationbased on the change in curvature 22CPC of the central portion 22CP isabout −2 D along axis 12B and about −2 D along axis 12C.

The cylinder of the eye can be corrected with many ratios of the longand short dimensions of the oval support 100. For example, an eye havinga far vision refraction of 0 D sphere −1 D cylinder at axis of 180degrees can be corrected with the oval protrusion. The long innerdimension 112B can be aligned along the 90 degree axis and the shortinner dimension 112A can be aligned along the 180 degree axis. When theprotrusion elevation height is about 50 microns, the oval support mayhave a long dimension of about 6 mm and a short dimension of about 4.2mm, as described above with reference to FIG. 2A-4. Many additionalcombinations of dimensions can be identified by a person of ordinaryskill in the art based on the teachings described herein. The protrusioncoupled to the oval support can provide about +2 D of optical poweralong axis 12B and about +2 D of optical power along axis 12Ccorresponding spherical near vision refraction of about −2 D sphere whenthe eye accommodates.

As the central and intermediate portions of the anterior lens capsulecan move forward together so as to provide optical correction inaddition to the curvature 22CPC of the protrusion 22CP, the amount ofaccommodation and corresponding near vision refraction of the eye can begreater than the amount provided by the curvature 22CPC of protrusion22CP. Alternatively or in combination, the intermediate portion 22I maybe coupled to support 100 so as to provide additional stretching of theouter portion 22O and peripheral portion 22P of the lens capsule asdescribed herein, such that the accommodation can be further increased.Based on the teachings described herein, a person of ordinary skill inthe art can conduct additional experiments and computer simulations soas to determine empirically the protrusion height and correspondingsizes and ratios of the short axis and the long axis so as to correctastigmatism when the eye accommodates.

As a small amount of astigmatism can be tolerated by the patient, theoval support can be used to increase the amount of accommodation of theeye and provide a small amount of astigmatism with acceptable vision,for example about 1 D astigmatism or less.

FIG. 3A shows a side view of the eye having an accommodating IOL 50positioned substantially within a lens capsule having the intermediateportion stiffened to increase accommodation. The accommodating IOL 50comprises a lens 52 and a haptic 54. The radially inward force of thecapsule in contact with haptic 54 as indicated with arrow 40 can movethe lens 52 forward to increase optical power of the eye and increasethe amount of accommodation of the accommodating lens 50.

The accommodating IOL 50 may be placed at least partially within thecapsule 22. The stiffening treatment of the capsule can be combined witha capsulorhexis to remove the central portion 22C of the anterior lenscapsule. The capsulorhexis can be performed during cataract surgery toremove the natural lens and allow placement of the accommodating IOL inthe lens capsule. The tissue of the intermediate portion 22I can bestiffened so as to decrease radial movement of the capsulorhexis edgeand increase accommodation of the accommodating IOL 50. The stiffeningtreatment of the intermediate portion inhibits radial motion of theintermediate portion 22I so as to increase elastic stretching of theperipheral portion 22P when the lens capsule stretches such that theperipheral portion can move the haptic with increased radially inwardforce as indicated with arrow 40. The stiffening treatment of theintermediate portion 22I can be performed before, during or after thecapsulorhexis, or combinations thereof. For example, the intermediateportion 22I of the anterior capsule can be stiffened prior tocapsulorhexis with the pupil dilated such that the curvature of thenatural lens is maintained, and such that the curvature corresponds tothe curvature of the non-accommodative eye. Following the capsulorhexis,the intermediate portion of the posterior capsule as shown above can bestiffened, for example.

The accommodating IOL 50 may comprise one or more components of knowaccommodating IOLs. The lens 52 may comprise a rigid material thatprovides accommodation when the lens 52 moves anteriorly. Alternativelyor in combination, the lens 52 may comprise a flexible material thatdeforms to increase the curvature when the eye accommodates. Example oflenses having components suited for use in accordance with embodimentsas described herein include the Crystalens™ HD IOL, Focus IOL™ IOL, andFlexOptic™ IOL.

FIG. 4A shows a side view of the eye being treated to stiffen theintermediate portion of the lens capsule with a probe 60. The probe 60may comprise a probe tip 62 at a distal end to emit one or more of anenergy or an agent 70 to treat and stiffen the intermediate portion 22I.The one or more of the energy or agent 70 may comprise laser energy,mechanical energy, electrical energy such as radiofrequency ormicrowave, or an agent such as chemical agent or nutritional agent. Theprobe 60 may comprise an elongate portion 68 for insertion into the eyethrough an incision in the cornea 12 near a periphery of the cornea. Theincision can be of any size, preferably no more than about 2 mm, morepreferably no more than about 1 mm. The probe 60 may comprise anelongate handle 64 for the surgeon to grasp the probe. A cable 66 canconnect the probe to a source of the one or more of the energy or agent70 and circuitry to deliver the energy or agent 70 in accordance with atreatment profile. The probe tip 62 can be moved around the eye to treatthe intermediate portion of the anterior capsule, for example. The eyemay be dilated, for example with cycloplegia, so as to expose theintermediate portion 22I for treatment. The cable may comprise one ormore of a channel to deliver the treatment agent, a waveguide todelivery electromagnetic energy such as fiber optic to deliver lightenergy, or an electrical conductor to deliver electrical RF energy tothe probe tip or electrical energy to a mechanical transducer, so as tostiffen the intermediate portion 22I.

The stiffening substance may comprises one or more of an adhesive, athermoreversible adhesive such as Poly(N-isopropylacrylamide)(hereinafter “p-Nipam”), a patterned microstructure based adhesive suchas a setae based adhesive, a glycoprotein based adhesive such as aglycosylated hudroxytryptophan, a curable adhesive, a tissue fixative, acrosslinker, a photo-sensitive crosslinker, or a substance to inhibitnutrients to the intermediate portion. The setae may comprise setaesimilar to gecko footpads having the attractive forces that hold thesetae to surfaces with van der Waals interactions between the finelydivided setae and the surface of the lens capsule. The substance can besuitable for a chemical reaction, such as a photochemical reaction. Thesubstance may comprise cross-linker, for example thiosulfate. Thesubstance may comprise as a photosensitive cross-linker, such asriboflavin.

The probe 60 can be used in many ways to treat the intermediate portion22I of the capsule. For example, the probe tip can be moved in acircular pattern such that intermediate portion 22I comprises an annularportion. The probe tip 62 can be moved to a plurality of treatmentlocations, with an amount of energy delivered to each location. Thetreatment profile can be configured such that tissue is stiffened ateach location without substantially shrinking the tissue of theintermediate portion 22I such that the refraction of the eye when notaccommodating is change less than about 1 D, for example less than about0.5 D when treated.

Treating the intermediate portion may comprise delivering one or more ofan energy or a substance to the intermediate portion. The energy maycomprise one or more of mechanical energy, electromagnetic energy, RFenergy, microwave energy, light energy, UV light energy, visible lightenergy or infrared light energy.

The agent 70 may comprise a substance such as one or more of anadhesive, a curable adhesive, a tissue fixative, riboflavin, or asubstance to inhibit nutrients to the intermediate portion, for example.The adhesive may comprise one or more of cyanoacrylate adhesive,temperature sensitive adhesive, thermoreversible adhesive or setae basedadhesive.

FIG. 4B shows a side view treatment of the eye to stiffen theintermediate portion of the lens capsule with a light beam. The one ormore of the energy or agent 70 may comprise a light beam. The light beammay comprise a light beam focused on the intermediate portion 22I of thelens capsule, for example the anterior capsule, such that theintermediate portion is stiffened. The light beam may comprise infrared,visible, or ultraviolet energy, for example, and the light beam maycomprised pulsed or substantially continuous wave (hereinafter “CW”)light energy from one or more of many sources such as a laser, an LED,or a lamp.

In many embodiments, the light energy is transmitted through the corneaof the eye and absorbed with the intermediate portion to treat theintermediate portion.

FIG. 4C shows a side view of treatment of the eye with a light beam 70Sto soften a portion 22S of the lens capsule located between theintermediate portion 22I and the central portion 22C. While many sourcesof light energy can be used, a femto second laser can be used at acontrolled depth corresponding to treatment of the lens capsule. Thestiffing treatment to the intermediate portion of the lens capsule canbe combined with the softening treatment. The softening of the capsulecan be accomplished by increasing the strength of the laser, increasingthe number of holes or slits cut in a given area. The cuts or holescould also be done in a way as to not completely penetrate the capsule.The hole density could also be varied over the surface of the capsule tocreate different optical affects such as increasing sphericalaberration, multifocality, coma etc. during accommodation. The holespattern could form a ring or cold be in a bulls eye pattern or just acentral dot. The procedure could be created on preferably the anteriorcapsule but could be accomplished on the posterior capsule or bothcapsules.

FIG. 4D shows a front view of a softening treatment portion 22S of theeye as in FIG. 4C. The softening treatment portion 22S may comprise anannular treatment zone, for example.

FIG. 4E shows the treatment as in FIGS. 4C and 4D located within thecapsule to inhibit penetration of the capsule. The softening beam 70Smay comprise a laser beam of a femto second laser, for example.Alternatively the softening beam may comprise a CW beam focused on thecapsule, for example.

FIG. 4F shows the retreatment of the capsule. The retreatment of thecapsule may occur when the eye has healed and when the vision of the eyehas been measured after the first treatment, for example at least aboutone day after the first treatment. The retreatment can be located at asecond intermediate portion of the lens capsule. The second intermediateportion 22I2 of the lens capsule corresponding to the second treatmentmay overlap at least partially with the first intermediate portion 22I,or can be separated. The second intermediate portion 22I2 may be locatedradially inward of the first intermediate portion to increase the amountof accommodation or adjust the far vision refraction of the eye, forexample when the first treatment under corrects the patient andadditional treatment can be helpful.

FIG. 5A shows a top view of a structure 80 to apply an agent to theintermediate portion of the lens capsule. The structure 80 may comprisean inner annular dimension, for example an inner annular diameter 82,and an outer annular dimension, for example an outer annular diameter 84corresponding to the dimensions of the intermediate zone 22I. Thestructure may comprise an absorbent structure having an amount of theagent disposed thereon, for example.

FIG. 5B shows a top view of the structure 80 as in FIG. 5A folded forinsertion through an incision, such that the structure 80 comprises anarrow elongate profile configuration 86 for insertion through theincision. The dimensional difference between the inner annular diameter82 and the outer annular diameter 84 correspond to a size of theincision, for example. The folded end may be advanced through theincision first, and the structure 80 unfolded within the eye to applythe agent to the intermediate zone with contact to the capsule.

FIGS. 5B1 and 5B2 show the structure 80 comprising an expanded wideprofile configuration, and narrow profile configuration for insertioninto the eye through an incision in the cornea, respectively. Thestructure can be inserted through an incision of no more than about 2mm, for example. The wide profile configuration may comprise an annularstructure, such as a ring or oval annular structure such as a C-ringannular structure. The structure 80 can be twisted for insertion throughthe incision in the narrow profile configuration and can expand to thewide profile configuration and adhered to the lens capsule as describedherein. The C-ring annular structure may be aligned with the lenscapsule so as compensate for broken zonules, for example.

FIG. 5B3 shows a narrow profile configuration for insertion into the eyethrough the incision with rotation of the structure 80 shown in FIG.5B1.

FIG. 5C shows a stiffening support 100 coupled to the intermediateportion of the capsule to stiffen the intermediate portion of thecapsule with the support. The treatment of the capsular tissue tostiffen the intermediate portion of the capsule may comprise couplingthe stiffening support to the tissue to decrease radial movement of thecapsule, such that stretching of outer portion 22O is increased. Thesupport 100 can be coupled to the tissue of the lens capsule in manyways, for example with an adhesive or mechanical clamping orcombinations thereof. The support 100 may comprise configurations,structures and insertion methods similar to structure 80 as describedherein.

FIG. 6A shows an apparatus 90 to apply a treatment profile of the one ormore of the agent or energy 70 so as to stiffen the intermediate portionof the lens capsule. The apparatus 90 comprises a source 92 of energy oragent, such as a laser to generate a laser beam or a reservoir tocontain an agent. The source 92 is coupled to circuitry 94 to deliverthe one or more of the agent or energy in accordance with the deliveryprofile. The circuitry 94 may comprise a processor 96 having a computerreadable medium having instructions of a computer readable medium storedthereon so as to delivery an amount of the one or more of the energy orsubstance 70 to the eye. The circuitry 94 is coupled to an outputcontrol 98 coupled to the probe 60, for example. The output control 98may comprise one or more of many devices to control delivery deliver theenergy or substance to the eye such as a pump, an optical shutter, anelectrical switch, or a gain control, for example.

FIG. 6B shows the treatment profile 74 to stiffen the intermediateportion of the lens capsule with the one or more of the energy orsubstance 70 delivered with the apparatus 90 as in FIG. 6A. Thetreatment profile 74 may comprise an intensity of or amount deliveredover a time period so as to stiffen the tissue of the lens capsule, forexample without substantially shrinking the tissue of the lens capsuleand such that the thickness of the lens capsule is substantiallymaintained. The tissue may be stiffened such that optical clarity of thetissue portion is substantially maintained.

Experimental and Computer Modeling

FIG. 7 shows a graph of radial accommodative force of the peripheralportion of the lens with stiffening of the intermediate portion based oncalculations. The radial force was determined using finite elementanalysis and known material properties and geometries of the lenscapsule. The finite element modeling used Abaqus™ software commerciallyavailable from Simulia of Providence, R.I.

The capsule was modeled with finite element shells having a uniformthickness of about 30 um. The intermediate portion of the lens capsulecorresponding to the stiffened tissue was constrained such that theradial position remained fixed but was allowed to move along the axis ofthe coordinate system, as described herein. The radial location of thestiffened intermediate portion of lens capsule tissue was fixed at aradial distance. The lens profile in the non-stretched lens conditioncorresponding to accommodation was used to determine the fixed radialdistance of the stiffened tissue of the intermediate portion of the lenscapsule. This fixed radius condition corresponds to treatment to stiffentissue when the eye accommodates. Alternatively, the tissue can bestiffened such that the radial distance of the intermediate portion isfixed at a radial distanced corresponding to a partially stretched lenscapsule, for example. The stiffened tissue can be adjusted, for examplewith retreatment. Although the initial force determined with the finiteelement modeling was somewhat higher for the normal lens capsule, forexample about 30 g, this elevated force can be related to modeling ofthe lens capsule with uniform thickness. Based on the teachingsdescribed herein, a person of ordinary skill in the art can model thelens capsule with varying thickness and material properties to determinethe radial force for the stiffening tissue treatment.

With the non-stiffened capsulorhexis, the inward force of the lenscapsule corresponding to accommodation decreased to about 4, 3 and 2grams with capsulorhexis diameters of 4, 5 and 6 mm respectively. Withthe stiffened capsulorhexis having the fixed radius of the capsulorhexisedge corresponding to treatment to stiffen tissue of the intermediateportion of the lens capsule, the inward force of the lens capsulecorresponding to accommodation increased to 6.5, 6.8 and 7.2 grams, withcapsulorhexis diameters of 4, 5 and 6 mm respectively.

The unexpected results of these calculations indicate that stiffening ofthe intermediate portion as described herein can increase accommodativeforce following capsulorhexis as compared to non-stiffenedcapsulorhexis. These calculations also indicate that stiffening of theintermediate portion of the normal lens capsule can increaseredistribute forces of the lens capsule so as to increase the amount ofaccommodation of the natural lens.

Experiments can be performed to determine the profile of the one or moreof the energy or substance so as to stiffen the intermediate portion ofthe lens capsule, for example without shrinking the intermediate portionof the lens capsule and such that the thickness of the stiffened tissueis substantially maintained to within about +/−30%, for example towithin 20%, of the pre-treatment thickness. For example, tissue can beheated to a temperature for a period of time corresponding to atemperature below the cauterizing temperature that can shrink tissue. Inmany embodiments, tissue can be heated so as to stiffen, for example soas to coagulate or denature collagen below the cauterizing temperature.For example, egg white can provide an in vitro model for thermal heatingsuitable to stiffen tissue.

Lens capsules can be treated with the one or more of the agent or energyas described herein. The capsules can be extracted, and the modulus ofthe lens capsule can be measured after stiffening treatment, forexample.

Following in vitro measurements, in vivo measurement can be performed onliving eyes. The change in refraction and accommodation can be measuredso as to ensure that the amount of accommodation increases by at leastabout ID for at least about 3 months in a primate animal model and therefraction can be measured so as to ensure that the refraction changesby no more than about 2 D, for example no more than about ID with atleast 1 D of increased accommodation.

Clinical trials can be performed to determine the amount ofaccommodation increased with the tissue stiffening as described herein.

Based on the teachings described herein a person of ordinary skill inthe art can determine the treatment profile 70 so as to treat tissue tostiffen the tissue of the intermediate portion of the capsule, forexample to stiffen without substantial shrinkage and in at least someembodiments such that the stiffened lenses capsule remains opticallyclear.

While the exemplary embodiments have been described in some detail, byway of example and for clarity of understanding, those of skill in theart will recognize that a variety of modifications, adaptations andchanges may be employed. Hence the scope of the present invention shallbe limited solely by the claims.

What is claimed is:
 1. A method of treating an eye having a lens and alens capsule, the lens capsule having a central portion, a peripheralportion and an intermediate portion, the peripheral portion connected tozonules of the eye, the intermediate portion corresponding to a locationbetween the intermediate portion and the central portion, the methodcomprising: treating the intermediate portion of the capsule to stiffenthe intermediate portion to increase curvature or movement anteriorly ofat least a portion of the lens when the eye accommodates.
 2. The methodof claim 1, wherein the increased curvature of the lens comprises anincreased amount curvature of a natural lens of the eye or an increasedamount curvature of an IOL, and wherein the increased movementanteriorly comprises an increased amount of axial movement of thenatural lens of the eye or an increased amount of axial movement of theIOL implanted in the eye.
 3. The method of claim 1, wherein theintermediate portion is treated to stiffen the intermediate portionwithout shrinking substantially tissue of the intermediate portion suchthat far vision of the eye is maintained.
 4. The method of claim 1,wherein the intermediate portion is stiffened such that far vision ofthe eye is maintained to within about ID and the an amount ofaccommodation of the eye is increased by at least about ID.
 5. Themethod of claim 1, wherein the intermediate portion of the capsule istreated so as to maintain optical clarity of the intermediate portionwhen the intermediate portion is stiffened.
 6. The method of claim 1,wherein the capsule comprises an anterior capsule and the intermediateportion comprises an intermediate portion of the anterior capsule. 7.The method of claim 6, wherein the lens comprises a natural lens of theeye and wherein the treatment is applied to the intermediate portion ofthe anterior capsule without penetration of the capsule.
 8. The methodof claim 7, wherein the central portion of the capsule is coupled to theperipheral portion of the capsule with the stiffened intermediateportion such that the central portion is moved forward when the eyeaccommodates and the peripheral portion moves inward.
 9. The method ofclaim 8, wherein the central portion of the lens capsule movesanteriorly along an axis of the eye a first amount and the intermediateportion moves anteriorly along the axis a second amount, the firstamount greater than the second amount such that the curvature of thecentral portion is increased when the eye accommodates.
 10. The methodof claim 1, wherein the capsule comprises a posterior capsule and theintermediate portion comprises an intermediate portion of the posteriorcapsule.
 11. The method of claim 1, wherein treating the intermediateportion comprises delivering one or more of an energy or a substance tothe intermediate portion.
 12. The method of claim 11, wherein the lightenergy is transmitted through the cornea of the eye and absorbed withthe intermediate portion to treat the intermediate portion.
 13. Themethod of claim 11, wherein the one or more of the energy or thesubstance is delivered to the intermediate portion of the capsule with aprobe tip and wherein the probe tip is introduced into an anteriorchamber of the eye through an incision in an outer portion of a cornea.14. The method of claim 11, wherein the one or more of the energy or thesubstance is delivered to the intermediate portion of the capsule with aprobe tip and wherein the probe tip is introduced into an anteriorchamber of the eye through an incision in an outer portion of a cornea.15. The method of claim 1, further comprising performing a capsulorhexisto remove the central portion of the capsule and placing an intraocularlens within the capsule.
 16. The method of claim 15, wherein thestiffened intermediate portion decreases radial movement of thecapsulorhexis edge such that radially inward force of the peripheralportion is increased by at least about 1 g when the eye accommodates.17. The method of claim 15, wherein the intermediate portion of thecapsule is treated before performing the capsulorhexis to remove thecentral portion of the capsule, and wherein at least a portion of thestiffened intimidate portion of the capsule remains to move theperipheral portion inward when the eye accommodates with the intraocularlens.
 18. The method of claim 15, wherein the stiffened intermediateportion supports the peripheral portion such that the peripheral portionmoves the intraocular lens forward with a radially inward force of atleast about 3 g.
 19. The method of claim 1, further comprisingretreating the lens capsule with a second treatment to stiffen the lenscapsule at least about one day after the treatment to increase theamount of accommodation of the eye.
 20. The method of claim 1, furthercomprising treating tissue of the lens with a softening treatmentlocated inward of the intermediate portion so as to couple the stiffenedintermediate portion of the capsule to the softened tissue to increasethe amount of accommodation of the eye.
 21. An apparatus to treat aneye, the eye having a lens comprising a capsule, the apparatuscomprising: a delivery device to couple to an intermediate portion thecapsule to deliver one or more of an energy or a substance to theintermediate portion; circuitry coupled to the delivery device todeliver the one or more of the energy or the substance to the eye tostiffen the intermediate portion.
 22. An apparatus to treat an eye, theeye having a lens and a capsule, the lens capsule having an intermediateportion extending between a central portion of the lens capsule and aperipheral portion of the lens capsule, the apparatus comprising: adeflectable structure to couple to the intermediate portion the lenscapsule to deliver an agent to the intermediate portion so as to stiffenthe intermediate portion and wherein the deflectable structure comprisesan amount of the agent sufficient to stiffen the intermediate portion.23. A method of treating an eye having a lens and lens a capsule, thecapsule having a central portion and a peripheral portion connected tozonules of the eye, the method comprising: applying an adhesive to anintermediate portion of the capsule to stiffen the intermediate portionto increase one or more of curvature or movement of the lens when theeye accommodates, the intermediate portion located between the centralportion and the peripheral portion.